急问？？？为什么在内存DC上画图，刷新几次才能得到数据？

Question

代碼太多了 建議改用GDI+ 多快好省 Graphics::DrawCachedBitmap也能先在cache裏面做好圖 快速顯示
VOID Example_DrawCachedBitmap(HDC hdc)
{
   Graphics graphics(hdc);   // Create Bitmap object.
   Bitmap bitmap(L"Climber.jpg");   // Use the Bitmap object to create a CachedBitmap object.
   CachedBitmap cachedBitmap(&bitmap, &graphics);   // Draw the cached bitmap.
   graphics.DrawCachedBitmap(&cachedBitmap, 20, 10);
}

Answer 1

把if(pDoc-> m_nwidth     >     0     &&     pDoc-> m_nheight     >     0     &&     pDoc-> m_hbitmap     !=     NULL)    
                      {    
                                              SetScrollSizes(MM_TEXT     ,CSize(pDoc-> m_nwidth*pDoc-> m_iZoomFactor/100,    
                                                                      pDoc-> m_nheight*pDoc-> m_iZoomFactor/100));    
                      }     这句去掉试试